Method of vulcanizing rubber



Patented June 12, 1945 I foot Corporation, Akron, hio,- a corporation of -Delaware a v N0 Drawing; Original application June 29, 1938, F Serial No. 216,627. Divided and this application January 28, 1943; Serial No. 473,779

reclaims; (01. 260-788) -'I"l'iis'--invention relates to compounds useful in the vulcanization or rubber anemone particularly, to amine salts of certain thiodiazoles as vul- Ri iskani arylis roup and R1 and R2 may he aliphatic, aromatic 'or heterocyclic groups or hy- 1dz:ogen,-Jnot. more than one hydrogen beingpresent. -L Furthermore, R1 and R2 may constitute, conjointly with the imino or; nitrogen-containing groum a zheterocyclic nucleus, such as the pipertidyl'ggroup. ;Where guanidine salts areiormed, a.; special case, arises-{under the "general formula given above which 'may be represented by the sub-generic formula:

1 canization accelerators. I v

It has been found that the, 2-me1capto 4-aryl 5 )G NH -G I thiodiazoles 5-thiones may be reacted with amines s: I mm- 1 fi ei i ffii td? 1393123 m; 2 3 535? 1 2 g? u I I I I p .o e e o yc 1c roupsoryfggmi' z g i tImone drogen. ltwill thus bevseen that the mercapto CHI compound may be reacted with compounds of the I general'formula y I I 8: ---SHv v I -/1 /'R1 I II I NH which may be prepared in the form of its salt 15 a R I new phenyl lhydrazine carbon disulfi'de aridea whyfl xid jnwth xf uowingvmanner; inzwhich-RrHand'Ra are hydrogen, aliphatic or 1 aromatic radicals or, With' the imino or NH I II I fig ligtconsntute a, heterocychc or a guanidme I I v I, v Among the various amines with'which the p p fj1 I N 5; f' z-mercapto 4-aryl thiodiazoleiE-thione may be I reacted arecyclohexylamine, benzylamine, piper- C NH-NH'-css1 cs, i I idine, dicyclohexylamine, dibutylamine, N-ethyl I cyclohexylamine, N-butyl cyclohexylamine, N- N 313, phenyl" cyclohexylamine; dibenzylamine, meta I I I L rphenyle-ethylam-ine,'N-butyl -beta --phenyl" ethy1- m amine, :primary floutylamine, amylaminer [fur- S I fury-laminar-:tetrahydrofrrrfurylamine,"difurfuryl Qthenthiodiazoles mayrbe prepared in the same n r lditetl'ahlfdrofulfmylamm? and manner suchashthose in which the phenyl..subh x i i r ea salts stituent of the foregoing compound" has been reamiare mcludedwlthmfihe placed-by-tolyl, xy1y1, naphthyl, cumyl, and the term the pp nd d ms- Iuke I r Among-the' guammnesfound su table are'di- These amine:salts.:of:.2-mercapto 4-aryl thioy T l'dltol, guamdme" iy l diazolefi-thiones have.been founduseful as acti- P i Naphenyl N F iguamdme vatorslforaccelerators of the vulcanization of rub- 'dlfyclohexyl i t W010 ber'and may be employed'lin conjunction With P N 'tolyl guamdmea N' N 'tolyl i mercaptobenzdthiazole IandTO-ther accelerators 40 idme phenyl tolyl guanidme and" other similar commo'nlyused in rubloer. The general formula guamdme s' I 1.01 the class ofsactivatorsz herein described may f t amme n be readny formed by be represented as followsz: mitting the thiod azole to react, preferably in I ,7 solution, with the 'selectedamme or guamdme.

' E 1 II The conditions forlthe rreactionaare not critical, 5 M room .temperatureusually being sufiicientbut the r p reaction mixturewmay require to .be slightly warmed. .under reflux or, 'wher'echeat :is evolved, cooling may .ibe necessary. The, startingsmaterials willordinarily react in molecularorequiv alent proportions but ran excessflof either-:one

may be present. where this is..advisable in order to promote-t the reaction. The..fo1lowing exampies. illustrate amethod of formation of these compounds, although it will be understood that the invention is not limited thereto.

Example 1 The piperidine salt of 2-mercapto 4-phenyl thiodiazole 5-thione was prepared from 15 parts of the mercaptan dissolved in 50 parts of acetone at room temperature and treated with 6.8 parts of piperidine excess). Heat was evolved and a White crystalline solid separated. The mixture was cooled, diluted with 20 parts of petroleum ether, filtered and the solid Washed with petroleum ether and air-dried. The yield amounted to 20.5 parts of the piperidine salt in the form of a white crystalline solid, melting point 1567 C. This corresponds to a theoretical wield. Analysis: Calculated for C13I'I1'1N3S32 S, 30.86. Found: S, 31.16. Hence, the formula is assumed to be 01H N-N H on CH 1 u I/ s:o\ C-S1Tl\ /oH,

s H OHr-CH! Example 2 The cyclohexylamine salt was prepared by dissolving partsof 2-mercapto 4-phenyl thiodiazole 5-thione in 50 parts of acetone at room temperature and treating this with 7.2 parts of cyclohexylamine (10% excess) dissolved in 10 parts of acetone. An exothermic reaction ensued and the reaction mixture was cooled in an ice bath and d luted with ether and petroleum ether to induce crystallization of the cyclohexylamine salt. Finally, the pale tan crystals which separated were filtered off, washed with petroleum ether and dried. There were thus obtained 19.2 parts of the desired salt, a 90% yield. The melting point was,180 181 C. Analysis: Calculated for C14H19N3S3: S, 29.53. Found: S, 30.07. Hence, the formula is assumed'to be o,H,N --N 11 omen,

I I I s:o /CSlTTH-CH\ on; s H onion,

Example 3 Example 4 Thedioyclohexylamine salt was formed from 8.4 parts of the mercaptan dissolved in 25 parts of acetone at room temperature and a solution of 7 parts of dicyclohexylamine, a 5% excess, in 15 parts of acetone. Heat was evolved and a crystalline solid separated. The mixture was cooled, diluted with 75 parts of petroleum ether,

and the cream-colored crystals filtered off, washed with petroleum ether, and dried. Ayield of 13 parts, or 86% of the theoretical, was obtained of a compound melting at 214-16 C. with decomposition. Analysis: Calculated at CzoHzaNsSst 5, 23.59. Found: S, 23.58. Hence, the formula is assumed to be The sym. diphenylguanidine salt of Z-mercapto 4-phenyl thiodiazole 5-thione was prepared as follows: Fifteen parts of the meroaptan and 15 parts of sym. diphenylguanidine were warmed under reflux in 100 parts of alcohol for one hour. The reaction mixture was concentrated to a volume of '75 parts, diluted with water until a permanent turbidity developed and cooled in the ice bath. A heavy amber oil separated and crystallized upon further standing. The solid was broken up, filtered off, and dried. A yield of 26 parts, or of the theoretical, was obtained of a solid melting at -123 C. The formula of this, product is assumed to be 1 Other salts may be prepared, in a manner similar to that set. forth in the foregoing examples, from the various 2-mercapto' 4-aryl thiodiazole 5-thiones and the various amines, including the guanidines mentioned herein.

Certain of the compounds were tested in rubber to determine their activating power. A test stock was selected consisting of ,Parts Smoked sheet 1 100.00 Zinc oxid 5.00 Sulfur 3.00 Mercaptobenzothiazole 0.30 Activator 0.20

The various salts were added to the stock in the amount indicated, these salts being identified as follows:

No. Name Piperidine salt of z-mercapto -phenyl thiodiazole S'thione.

Cgczlghexylamine salt of 2-metcapto 4-phenyl thiodiazole lone.

Benzylanune salt of 2-mercapto 4-phenyl thiodiazole E-thione.

Disctyfilohexylamine salt of 2-mercapto 4-pheny1 thiodiazole lone.

Syrn. diphenylguanidine salt of 2-mercapto 4-pl1enyl thiodiazole 5-thione.

cam-w NH The results obtained as a result of testing these stocks after cure are shown below:

' Modulus at- Cure, mins. Tensfle Ult. No. a break at F. kgs 5 2 Elong.

It will be noted that satisfactory cures, as indicated by the physical strength, were obtained in comparatively short periods of time, thus "indicating the activating effect of the compounds.

This application is a division of my application Serial No. 216,627, filedJune 29, 1938, now matured into Patent No. 2,331,? 19.

The new compounds herein described are thus useful as activators in the acceleration of the vulcanization of rubber and may be employed.

with other accelerators commonly employed in rubber manufacture. Although'only the preferred form of the'invention has been described in detail, it will be apparent-to those skilled in the art that the invention is not limited-thereto but that var-1 ious modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims in which it is intended to cover all features of patentable novelty I residing therein.

What I claim is: t

1. The method which comprises vulcanizing rubber in the presence of an amine salt of a 2- mercapto 4-aryl thiodiazole 5-thione.

2. The method which comprises vulcanizing rubber in the presence of an aminesalt of z-mercapto 4-phenyl thiodiazole' 5-thione.

3. The method which comprises vulcanizing rubbel in the presenceof a. heterocyclic amine salt of a Z-mercapto 4-aryl thiodiazole 5-thione,

4. The method which comprises vulcanizing rubber in vthe presence of a piperidine salt of 2- mercapto 4-phenyl thiodia'zole 5-thione.

5. A rubber product which has been vulcanized in the presence of an amine salt of a Z-mercapto 4-aryl thiodiazole" 5-thione.

6. A rubber product-which has been vulcanized in the presence of an amine salt of a 2-mercapto 4-phenylthiodiazole 5-thione. 1

7. A rubber product whichhas been vulcanized in the presence of a heterocyclic amine salt of a Z-mercapto 4-aryl thiodiazole 5-thione.

8. A rubber product which has been vulcanized in the presence of a piperidine salt of Z-mercapto 4-ph'eny1 thiodiazole 5-thione.

GEORGE w. WATT.- p 

